﻿// Upgrade NOTE: replaced '_Object2World' with 'unity_ObjectToWorld'

Shader "Custom/SingleTexture"
{
	Properties
	{
		_Color("Color Tint",Color) = (1,1,1,1)
		_MainTex("MainTex",2D) = "white"{}
		_Specular("Specular",Color) = (1,1,1,1)
		_Gloss("Gloss",Range(8.0,256)) = 20
	}
	SubShader
	{
		Pass
		{
			Tags{"LightMode" = "ForwardBase"}

			CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "Lighting.cginc"

			fixed4 _Color;
			sampler2D _MainTex;
			float4 _MainTex_ST;//纹理名_ST 可以得到纹理的缩放和平移（偏移）值------即scale and transform
			fixed4 _Specular;
			float _Gloss;

			struct a2v
			{
				float4 vertex:POSITION;
				float3 normal:NORMAL;
				float4 texcoord:TEXCOORD0;//保存第一组纹理坐标
			};
			struct v2f
			{
				float4 pos:SV_POSITION;
				float3 worldNormal:TEXCOORD0;
				float3 worldPos:TEXCOORD1;
				float2 uv:TEXCOORD2;
			};

			v2f vert(a2v v)
			{
				v2f o;
				o.pos = UnityObjectToClipPos(v.vertex);
				o.worldNormal = UnityObjectToWorldNormal(v.normal);
				o.worldPos = mul(unity_ObjectToWorld, v.vertex).xyz;
				o.uv = v.texcoord.xy * _MainTex_ST.xy + _MainTex_ST.zw;
				return o;
			}
			fixed4 frag(v2f i):SV_TARGET
			{
				fixed3 worldNormal = normalize(i.worldNormal);
				fixed3 worldLightDir = normalize(UnityWorldSpaceLightDir(i.worldPos));
				fixed3 albedo = tex2D(_MainTex, i.uv).rgb * _Color.rgb;
				fixed3 diffuse = _LightColor0.rgb * albedo * max(0, dot(worldNormal, worldLightDir));
				fixed3 ambient = UNITY_LIGHTMODEL_AMBIENT.xyz * albedo;

				fixed3 viewDir = normalize(UnityWorldSpaceViewDir(i.worldPos));
				fixed3 halfDir = normalize(worldLightDir + viewDir);
				fixed3 specular = _LightColor0.rgb * _Specular.rgb * pow(max(0, dot(worldNormal, halfDir)), _Gloss);
				return fixed4(ambient + diffuse + specular, 1.0);
			}
		ENDCG
		}
	}
	Fallback "Specular"
}
